1. Field of the Invention
The present invention is an oxidative process for the conversion of 21-unsaturated progesterones to the corresponding 3,5-secoandrost-5-one-3,17.beta.-dioic acid.
2. Description of the Related Art
The 21-unsaturated progesterones (I) are known compounds, see J.A.C.S., 82, 1709 (1960) and U.S. Pat. Nos. 2,727,905 and 4,324,878.
The oxidation of the steroid A-ring by ozone (O.sub.3) is known, see J.O.C. 23, 1787 (1958), U.S. Pat. No. 3,285,918 and European Patent Application 88300697.5 published Aug. 3, 1988 as European Publication Number 277,002 A2.
The oxidation of the steroid A-ring by MnO.sub.4.sup.-1 /IO.sub.4.sup.-1 is known, see J. Med. Chem., 27, 1690 (1984) and European Patent Application 88300697.5 published Aug. 3, 1988 as European Publication Number 277,002 A2.
The oxidation of a steroidal C.sub.17 enone side chain to the corresponding 17.beta.--COOH by ozone has been reported, see J.A.C.S. 78, 1414 (1956). The cleavage of 1,3-dicarbonyls is known, see J.C.S. Chem. Comm., 1055 (1968). However, the oxidation of an alkoxyoxalkyl to give a carboxylic acid has not been reported.
The known methods of producing the 17.beta.-carboxylic-3,5-secoandrostanes required that the particular C.sub.17 side chain desired in the secosteroid (II) be present in the starting material to be oxidized or to a group which following oxidation of the steroid A-ring could readily be converted to the desired C.sub.17 side chain, see, for example, European Patent Application 88300697.5 published Aug. 3, 1988 as European Publication Number 277,002 A2 on page 1167, lines 49-52. The process of the present invention differs from known methods because the one step process produces oxidation involving both ends of the steroid molecule in a simultaneous reaction. The use of glyoxylates as 1,3-dicarbonyls in an oxidation reaction is novel.